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re-add gen_safe_read_write

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Awal Garg 2018-08-17 22:27:48 +05:30 committed by Fabian
parent fb9a6e714a
commit 2f5b1311c6
1 changed files with 117 additions and 0 deletions
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117
src/rust/codegen.rs
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@ -748,3 +748,120 @@ pub fn gen_push32_ss32(ctx: &mut JitContext, imm: ImmVal) {
ctx.builder.instruction_body.store_aligned_i32();
ctx.builder.free_local(new_esp_local);
}
fn gen_safe_read_write(
ctx: &mut JitContext,
bits: BitSize,
address_local: &WasmLocal,
fn_idx: u16,
) {
let builder = &mut ctx.builder;
builder.instruction_body.get_local(address_local);
// Pseudo: base_on_stack = (uint32_t)address >> 12;
builder.instruction_body.push_i32(12);
builder.instruction_body.shr_u32();
// scale index
builder.instruction_body.push_i32(2);
builder.instruction_body.shl_i32();
// Pseudo: entry = tlb_data[base_on_stack];
builder
.instruction_body
.load_aligned_i32_from_stack(global_pointers::TLB_DATA);
let entry_local = builder.tee_new_local();
// Pseudo: bool can_use_fast_path = (entry & 0xFFF & ~TLB_READONLY & ~TLB_GLOBAL & ~(cpl == 3 ? 0 : TLB_NO_USER) == TLB_VALID &&
// (address & 0xFFF) <= (0x1000 - (bitsize / 8));
builder.instruction_body.push_i32(
(0xFFF & !TLB_READONLY & !TLB_GLOBAL & !(if ctx.cpu.cpl3() { 0 } else { TLB_NO_USER }))
as i32,
);
builder.instruction_body.and_i32();
builder.instruction_body.push_i32(TLB_VALID as i32);
builder.instruction_body.eq_i32();
builder.instruction_body.get_local(&address_local);
builder.instruction_body.push_i32(0xFFF);
builder.instruction_body.and_i32();
builder
.instruction_body
.push_i32(0x1000 - if bits == BitSize::WORD { 2 } else { 4 });
builder.instruction_body.le_i32();
builder.instruction_body.and_i32();
// Pseudo:
// if(can_use_fast_path) leave_on_stack(mem8[entry & ~0xFFF ^ address]);
builder.instruction_body.if_i32();
builder.instruction_body.get_local(&entry_local);
builder.instruction_body.push_i32(!0xFFF);
builder.instruction_body.and_i32();
builder.instruction_body.get_local(&address_local);
builder.instruction_body.xor_i32();
let phys_addr_local = builder.tee_new_local();
match bits {
BitSize::WORD => {
builder
.instruction_body
.load_unaligned_u16_from_stack(global_pointers::MEMORY);
},
BitSize::DWORD => {
builder
.instruction_body
.load_unaligned_i32_from_stack(global_pointers::MEMORY);
},
}
builder.free_local(entry_local);
builder.instruction_body.call_fn(fn_idx);
// now store the value on stack to phys_addr
builder.instruction_body.get_local(&phys_addr_local);
match bits {
BitSize::WORD => {
builder
.instruction_body
.store_unaligned_u16(global_pointers::MEMORY);
},
BitSize::DWORD => {
builder
.instruction_body
.store_unaligned_i32(global_pointers::MEMORY);
},
};
builder.free_local(phys_addr_local);
// Pseudo:
// else { safe_readXX_slow(address); fn(); safe_writeXX_slow(); }
builder.instruction_body.else_();
builder.instruction_body.get_local(&address_local);
match bits {
BitSize::WORD => {
gen_call_fn1_ret(builder, "safe_read16_slow");
builder.instruction_body.call_fn(fn_idx);
let new_val_local = builder.set_new_local();
builder.instruction_body.get_local(&address_local);
builder.instruction_body.get_local(&new_val_local);
gen_call_fn2(builder, "safe_write16_slow");
builder.free_local(new_val_local);
},
BitSize::DWORD => {
gen_call_fn1_ret(builder, "safe_read32s_slow");
builder.instruction_body.call_fn(fn_idx);
let new_val_local = builder.set_new_local();
builder.instruction_body.get_local(&address_local);
builder.instruction_body.get_local(&new_val_local);
gen_call_fn2(builder, "safe_write32_slow");
builder.free_local(new_val_local);
},
}
builder.instruction_body.block_end();
}